The present invention is directed to bicycles and, more particularly, to a bicycle disk brake caliper.
Bicycling is becoming an increasingly popular form of recreation as well as a means of transportation. Moreover, bicycling has become a very popular competitive sport. Whether the bicycle is used for recreation, transportation or competition, the bicycle industry is constantly improving their components. One particular component of the bicycle that has been extensively redesigned over the past years is the braking system.
There are several types of bicycle brake devices currently available on the market. Examples of some types of common bicycle brake devices include rim brakes, caliper brakes and disc brakes. If a rider wants a very high performance brake system, then the rider typically wants a disc brake system. Disc brake systems provide substantial braking power in relationship to the amount of braking force applied to the brake lever. Moreover, disc brake systems typically provide a high level of braking consistency in all types of weather and riding conditions. However, one problem with disc brakes is that the hydraulic or actuating fluid can become overheated such that vapor-lock occurs. In other words, the heat generated by braking results in the hydraulic fluid increasing in volume so as to cause the brake pads to engage the brake disc even when the brake lever is in the release position.
In prior art disc brake systems, several methods have been used to avoid vapor-lock. For example, the caliper housing may be made larger to absorb more heat, a larger brake disc with a wider surface area may be used to dissipate more heat, or brake or friction pads which do not transfer the heat to the caliper housing as readily as conventional friction pads may be used. Vapor-lock also can be suppressed by using high quality hydraulic fluid. Other known systems provide separate cooling systems that circulate a cooling fluid through a cooling chamber that is either attached to the caliper housing or formed as part of the caliper housing. However, none of the systems optimally cool the hydraulic fluid used to operate the brake.